LablGtkSourceView are the OCaml bindings for GtkSourceView, a GTK widget which extends the standrd GTK text widgets implementing syntax highlighting, automatic indentation, and other typical features of source editors.
Using LablGtkSourceView you can instantiate and use GtkSourceView widgets in OCaml programs which use GTK through the LablGtk interface.

GPL

Some code to make it relatively easy to develop custom tree models using LablGTK (GTK+ 2.0 in OCaml).
This means that you can have a tree structure coded naturally in OCaml and treat it more or less directly as a tree model, instead of having to shove values into a GTree.tree_store. There are some caveats as described in the README file.

BSD

Caml for Scintilla is a free source and binary package which adds syntax coloring for the Objective Caml language to the multi-platform (Win32 and GTK+) Scintilla editing component and SciTE text editor.

Public Domain

A simple GUI for OCaml. It offers two kinds of widgets, to wit, buttons and an Emacs like mini-editor.The idea is to create a GUI with a very small footprint, that is easy to handle for final users, and productive for developers.

Osiris is very-easy-to-use GUI (graphical user interface) system for OCaml. It's built on top of the OCaml Win32 native API binding and enable the creation and control of most of the standard user interface components.